Johnson & Johnson was informed by the US Food and Drug Administration that millions of doses of the Covid-19 vaccine produced at a troubled plant can't be used because of possible contamination issues.
In a Friday statement, the FDA said several batches of vaccine manufactured at the Emergent BioSolutions facility in the city of Baltimore are not suitable for use. Each batch is known to correspond to several million doses.
Neither the agency nor J&J revealed the precise number of doses, but the New York Times placed the number at 60 million, quoting people familiar with the matter.
These actions followed an extensive review of records, including the production history of the facility and the testing performed to evaluate the quality of the product, said FDA scientist Peter Marks.
The Emergent plant was ordered to pause production in April several weeks after it was determined that batches of substance used to produce the J&J vaccine were cross-contaminated with ingredients from the AstraZeneca vaccine, ruining a reported 15 million J&J doses.
The FDA is still deciding whether to allow the factory to reopen.
Sixty million AstraZeneca doses produced there and earmarked to be donated abroad are currently being inspected for quality before they can be shipped.
All of the J&J vaccines distributed and used in the United States so far were made in the Netherlands, not in Baltimore.
On the other hand, the FDA said it was green-lighting two batches of J&J vaccine made at the plant - that is to say, 10 million doses of the one-shot regimen. Additional J&J batches remain under review.
Johnson & Johnson has committed to producing safe, high-quality vaccines to bring health and hope to people everywhere, said J&J executive vice-president Kathy Wengel.